The "Edit parent" button disappears if you click on it twice on Flamingo

Steps to reproduce:

1. Set the wiki to use the Flamingo skin
2. Go to http://localhost:8080/xwiki/bin/edit/Sandbox/TestPage1?editor=wiki
3. Click on the "Edit parent" button -> the Parent input field appears (step1.png)
4. Set a new parent and click anywhere on the page -> the Parent input field but also the "Edit parent" button disappear (step2.png)